Emergency release for electric switch locks



W. C. MCWHIRTER EMERGENCY RELEASE FOR ELECTRIC SWITCH LOCKSl Aug. 5,1947.

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EMERGENCY RELEASE FOR ELECTRIC SWITCH LOCKS Filed Dec. 12, 1945 5 Sheets-Sheet 3 HIS ATTORNEY atented ug. 5, 194'? EMERGENCY RELEASE FOR ELECTRIC SWITCH LOCKS William C. McWhirter, Wilkinsburg, Pa., assigner to The Union Switch & Signal Company, Swissvale, Pa., a corporation of Pennsylvania Application December 12, 1945, Serial No. 634,560

9 Claims. (Cl. l0-346) My invention relates to an emergency release for electric switch locks.

As is well known, electric switch locks are commonly provided for the control of outlying switches which are operable by a manual lever, and they function to prevent operation ofthe lever away from its normal position except when the lock is released. The locking of the lever is usually eected by means of a dog controlled by an electromagnet and cooperating with a locking segment operatively connected with the lever, While the releasing of the lock is normally effected by energizing the electromagnet over a control circuit controlled from a distant point such as a signal tower, a telegraph station or a signal.

With locks of this type it sometimes happens that the usual means for releasing the lock fails due for example to a failure in the source of power for the control circuit, a break in the control circuit due to storms, etc., and one object of my invention is to p-rovide novel means for releasing the lock under these conditions.

Ano-ther object of my invention is to provide emergency release means which can be operated by the usual switch padlock key, but not until after a telltale device, such as a standard car seal, is broken to visibly indicate to the proper officials that an emergency release has been effected.

Another object of my invention is to provide latch means which is effective when the emergency release means are operated to latch the lock in its unlocked position until a maintainer subsequently operates the latch to permit the lock to return to its normal locked position.

According to one form of my invention, the emergency release mechanism is mounted on the inside of the lock mechanism in such manner thatto insert the key into the release mechanism it is necessary to lift a swinging cover, and this mechanism comprises a lifter block effective when lifted to raise the locking dog out of the notch in the locking segment. The lifter block is operated by a lifter spring which, inv turn, is operated by the key. The lifter spring provides a means whereby proper release of the lock dog may be obtained by svvitchmans keys having varying degrees of Wear and stroke, and limits the force or strain it is possible to apply to the lock mechanism 'by the key, whereby damage to the lock mechanism due to excessive `force is prevented. The lifter block may be shaped so that it also functions as a key register, and is further provided with means cooperating with the key Which insures its return to the normal position before the key can be Withdrawn from the release mechanism. A telltale to show operation of the release mechanism is obtained by providing a standard car seal which must be broken before the swinging cover can be rotated to the position to insert the switch key.

In a modified form of my invention the means on the lifter block, which cooperates with the key to insure the return of the lifter block to its normal position before the key can be removed from the mechanism, is omitted, and the lifter block is provided with means which cooperates with a spring biased latch in such manner that, when the lifter block is lifted to the position in which it raises the locking dog out of the notch in the locking segment, the latch will engage the lifter block and subsequently retain it in its lifted position until a maintainer subsequently operates the latch to permit the lock to return to its normal locked position.

Other objects and. characteristic features of my invention Will become apparent as the description proceeds.

Locks provided with emergency release mechanism embodying my invention are an improvement upon those shown and described in Letters Patent of the United States No. 1,126,834, granted to W. P. Neubert and W- E. Smith on February 2, 1915, for Electricswitch locks.

The present application is a continuation-inpart of my'prior application, Serial No. 533,709, filed on May 2, 1944, for Emergency release for electric switch locks.

I shall describe two forms of emergency releases for electric switch locks embodying my invention, and shall'then point out the novel features thereof in claims.

In the accompanying drawings, Fig. 1 is an end view of an electric lock provided With one form of emergency release means embodying my invention. Fig. 2 is a'vertical sectional view of the release means of the lock shown in Fig. 1. Fig. 3 is a sectional view taken onthe line III- III of Fig.' 2. Fig. 4 i-s a top View of the release means shown in the preceding views. Fig. 5 is a detail view of the key guide plate I forming part of the release mechanism illustrated in Figs. 2 and 3. Fig. 6 is a detail view showing a modication of the mechanism as illustrated in the preceding views. Fig. 7 is a View similar to Fig. 5 showing another modification of the mechanism as illustrated in the preceding views. Fig. 8 is a top view of the release means shown in Fig. '7.

Similar reference characters refer to similar parts in each of the several views.

Referring tofthe drawings, the reference character I designatesthe casing of VVan electric switch lock which may for example be similar to that described in detail in the Neubert et al. Patentk No. 1,126,834 referred to hereinbefore. Pivotally mounted within the casing I for rocking move-f ment about a rod 2 is a locking segment 3, the upper end of which is providedivwitha notch or recess ll adapted to coact with alockingzdog; 5.

4 tion Ia formed on a lifter block I'I. The lifter block is guided for vertical sliding movement between the bracket 8 and the key guide plate I0 by means of a vertical guide slot I'Ib which is milled in the block and which receives with some clearance the inner ends of two vertically aligned guide studs I9 secured to the bracket 8. The offset portion I'la of the lifter block carries a vertical lug llc which cooperates with the underside of the locking dog 5. The upper position to which the lifter block is free to move is limited by engagementof a shoulder Hd provided on the li'fter b-lock below the offset portion I'Ia in such position that when the lifter block reaches the .desired upper extreme position this shoulder will The locking segment 3 and locking dog. 5 corre' spond respectively to the locking plate 25 and locking dog 21 in said patent, "and the locking segment is operatively connected with lever latchv means which is not shown but which means is effective to prevent movement of the hand throw lever Yof la switch operating mechanism awa;T from its normalposition as long as the dog remains inthe notch li. The dog S'is normally adapted to be moved out of engagementrwith .the notch li by means of an electromagnet not shown, the energization ofrwhich willl generally be effected by a suitablecontrol circuit controlled fromva remotepoint such asa signal tower, a telegraph station, a signal or thelike.

leThe. portion of. the switch .lock thus far de scribed is well known, and if a more` detailed de;- scriptionv of this portion isdesired reference may be, had to the. said ANeubert et, al. Patent No. 1,-1265834.

.As was pointed. out hereinbefore, in electric switch locks ofthe Vtype described theY electric control4 circuits sometimes fail, and .when Vthis happens it isfdesirable to be able to release the lock by suitable emergency releasemeans in order -thattrains may be kept moving on or off -sidings under properly `authorized emergency instructions. For thispurpOse. I provide the improved emergencyY release means which I -shallnow describe.

As here shown, this release means comprises a suitableguide bracket 8 .riveted- .to `one wallof the casingV I. below the outer end of the locking dog 5 opposite an opening 9 inthe wall of-Athe casing. Akeyguide plate Ii)r (Figs. 2 and-5)Y is interposed between 4the bracket Band the adjacent .wall of the casing, and Ais providedl with a keyopening llawhichalignswith a-k'ey center stud I2 secured ,to theibracket 5. The key open-'- ing II is of such shape that itwill only permit switch` keys of a predetermined size and shape to beplaced on the key.V center` stud, and it follows therefore that .it serves as apreselecting means for the switch keys to limit the type of key which can be inserted into the release means. A- key regi'sterstud I3 (Figs. 3 and 4) .provided with notches I4 corresponding tothat provided in the key of the desired design is also secured to the bracket; 8.. at one -si'deof `the keycenter stud I2 so .that therelease- .can only be operated by the proper key.

The switch key. .cooperates with, a lifter spring I5l one end of which is curved around` a supporting .studrli` secured to` the bracket 8, andthe other end ofwhichbears against Vvan offset ppr- :Iwith a stop stud 20 secured to the bracket 8, whichstu-:l also serves to limit the extreme position to which the key can be rotated. The shoulder IIcl in addition to serving as a means to limit the upper movement of the lifter block l1 also cooperates with the key to force the lifter block downwardly to its lowermost extreme position before the keyv can be rotated tothe position to withdraw it from the key opening II.

A-tubular member 33 of suitable size to clear the .switchkeys is pressed into the opening 9, vand the outer end` of this member is iiared out- I'wardly and cooperates with a weatherproof pliable packingV disc 21a attached to a swinging cover 2l.UV The cover 2| is pivotally supported on the .outside of the .casing I on a pivot pin 22 mounted in spaced lugs 23, andis biased to a closed positio'nbya coilspring 24 surrounding the pin. One-end of this spring is secured to the casing I bymeans o'f.l a screw 25 and the other end engages a laterally .projecting pin 26 provided on the insideof the cover. The pliable packing disc 2Ia is not attached directly to the cover, but instead is attached to a metallic disc v2lb secured bymea'ns of a screw 3B against a ball shaped boss 2Ic on .the cover .to insure alignment of the packing'D disc with Iits seat. Foreign elements .which might otherwise enter and obstruct or interferewith the proper performance of the lock mechanism are therefore shut out. The lower end. of the cover is provided with a finger grip -2'1 to facilitate opening the cover, and cooperates with a car seal 32 looped through spaced stud projections 28 provided on the` casing I on opposite sides of the cover, whereby when the car seal isrinplacethecover. cannot be opened without breaking the seal.

- In operation, the emergencyrelease mechanism is only used in the event of failure of the normal ,release mechanism, andthen only after the trainman has obtained permission to break the seal, usually by telephone communication with a central dispatchers oice. When'the necessary permission is obtained, and the seal has been broken, the trainman then lifts the cover ZI by gripping -the-y iinger grip 21 and inserts the proper key same manner as when the dog is lifted out of the notch 4 by the electromagnet in the normal operation of the lock, and permits operation of the switch by the hand throw lever. The lifter spring l5 provides a means whereby proper release of the lock may be obtained by switchmans keys of the various degrees of wear and stroke and at the same time limits the force or strain which it is possible to apply by the key to a value which is insuflicient to damage the lock. The spring may be designed tol provide the necessary stroke required to lift the dog 5 clear of the notch 4 when the release is operated by keys having the maximum permissible wear, and a key with less wear or a new key will then merely deflect the spring by a slight amount after the lock dog is lifted to its released position. Before the key can be withdrawn from the release mechanism after the release has been operated it is necessary to restore it to a position in alignment with the key opening ll, and due to the stop stud this can only be done by rotating the key in a direction opposite to that in which it was rotated to operate the release. During the latter part of this rotation the key will engage the sho-ulder Id and force the lifter block downwardly to its lowermost position so that for future operation the lock dog 5 will be free to enter the notch 4 when the electromagnet is deenergized, and left in the normal manner under the control of the electromagnet.

Since it is necessary according to operating rules to obtain authorization to break the cover seal prior to operating the emergency release mechanism, the breaking of the seal becomes a matter of record. It then becomes the duty of the maintainer to inspect the electric lock as a whole and see that it is in proper operating condition before he reseals the key hole cover in its normally closed position. This eliminates any necessity for special keys and depo-sitories for these keys, and permits the use with safety of the usual switch key to operate the release mechanism.

If desired the key register stud I3 can be dispensed with and the desired key register can then be formed in the shoulder Hd as shown in Fig. 6 in such manner that the key will clear the shoulder when and only when the lifter block is in its lowermost position.

While only one type of mechanism seal is shown threaded through two stud projections on the end of the casing of the electric lock to insure against operation of the cover without removal of the seal, it is obvious that other designs of seals might be similarly applied.

Referring now to Figs. '7 and 8, the emergency release means in the yform here shown comprises a lifter block 45 which corresponds to the lifter block I1 of the emergency release means shown in the preceding views. The lifter block 4U is guided for Vertical sliding movement in the same manner that the lifter block l? is guided for vertical sliding movement, but instead of being provided with a shoulder which cooperates with the trainmans switch key toforce the block to its lowermost position before the key can be withdrawn from the lock, it is provided with a shoulder 45a which cooperates with an L shaped leaf spring 4| to bias the lifter block to its lowermost extreme position for a purpose which will be made clear presently. The leaf spring 4i is secured as by riveting to the bracket 8.

The lifter block 4i! further diiers from the lifter K withv key register means 4017 which takes the place of the key register stud I3 shown in the preceding views, and on its outside edge with a notch 40C which cooperates with a latching nger 42a formed on the depending arm 4'2b of a latch 42. The arm 42h of the latch extends downwardly through a vertical slot 43Y milled in a bar'44 which serves as a guide for the locking dog 5, and is pivotally supported within the slot 43 on a pivot pin 44a secured to the guide bar 44. The latch 42 Ais also provided with a horizontal arm 42h disposed above the upper edge of the guide bar 44. Th'e free end of this arm is bent at right angles to the remainder of the arm and carries a depending stud 42o which serves as a guide for a compressed coil spring 45 disposed between the arm and the upper edge of the guide bar 44. The spring 45 constantly biases the latch to such a position that the latching nger 42a will enter the notch 4c in the lifter block whenever the lifter block is moved to th'e position in which the notch aligns with the latching linger, and the notch is so disposed that it will align with the latching nger when and only when the lifter block is moved to'lits upper position.

With the release means constructed as shown in Figs. 7 and 8, it will be apparent th'at whenever the lifter block 40 is moved to its upper extreme position by a trainman to effect an emergency-release of the electric lock, the spring actuated latch 42 will automatically engage the lifter block and hold it in its upper position until the latch is subsequently manually operated to release the lifter block. Access to the latch can only be had by opening the cover of the lock, and since the maintainer is the only person that has the necessary authority to open th'e cover, it follows that once the lock is operated it can only be released by the maintainer. When the maintainer operates the latch to restore the lock, the lifter block will be urged to its lower or normal position by the combined forces due to gravity, the torque of the electromagnet armature, and the biasof the spring 4|, and upon reaching its lower position it will permit the locking dog to return to its normal locked position.

Although I have herein shown and described only two forms of emergency releases for electric switch locks embodying my invention, it is understood that various changes and modifications Vmay be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus describedy my invention, what I claim is:

1. In an electric lock for switches including the usual electrically controlled locking dog disposed within a casing and movable between a locking and a released position, the combination of emergency release means operable by the same key which is used to operate the switch padlock `for at times moving said dog to its released position independently of the usual release means comprising a lifter block slidably mounted in a guide bracket secured to one wall of said casing inside of the casing opposite an opening provided in said wall, a key center stud secured to said bracket, a lifter spring pivotally attached at one end to said guide bracket and cooperating at the other end with said lifter block, said spring being positioned to be operated by a key disposed on said key center stud and effective when operated to operate said lifter block, and means attached to said lifter block and effective when said block gais-,1111i 'is operated to operate said" dog to its reduced'posiition', said springf being 'proportionedto provide" the necessarylstrokerequird' to move said `dog to f 'itsreleased 'position' when `the releasefis' 'op-l erat'dby keys having? a predetermined' maximumv permissible amount 'ofi wear, and toV de'ect 'after" the dog-'reaches its released position vwhen there*- lea'se means is 'operated bykeys having less wear.'

`2."IriI an electriolcckfor switches includingi the usual electrically-lcontrolled locking dog, the l combination'of means'fop'erable bythe same keyT which'is used'to operatethe switch? padlock for mving said dogrto a'v released positionincluding" alifter'block eiiective'wli'en operated to 'one'position formoving'fsaidl'dogftoits released position, andfyieldable'- means 'actingi to transmit forceA` fromv thekeylto` the'block,` said means being so4 constructed that 'saidV block can' be operated to its one position byl keys havingvarying'. l,degrees of wear.

3.,'Inan electricA lock forswitches including: the i usual electrically i 'controlled locking dog,` the combination'of 4means operable by the `same Akey which is'used to operate the switch'padl'ock'for" moving said dog Ltda-'released' position including yieldable means for transmitting force fromE the key to said dogto move it to its'releasedposition, said yieldable means "being constructed `to enable a predetermined release :stroke 1 to -bebbtained with keys having-varying `degrees -of wear.

4; In'an electric lock for switchesincluding: the usualelectrically controlled `locking dog 'disposedy within a casing-, the Vcombination Iof -emeruV gency-release means operable by the-samekey' whichvis used-to operatejthe-switch padlock'for at times-releasing Ysaid dogindependentlyfof the usual-release means comprisingY a lifter block slidably mounted in a guide bracket secured toV onewall of saidecasing yinside of thefcasing vopposite an opening` provided insaid wall, a'key'zcnterA stud secured to'said bracket, a4 key vguideplate interposed between saidvbracket and said opening and provided with' ak'ey Vopening which aligns with said drst mentioned opening andsaid'key, center stuctsaid key opening :being'of such shape that it will onlyfpermit switchmans keys of. a predetermined'v size andshape vto be placedfonfthe' key'cnter stud, a" key" register stud securedto saidbackt at onesi'de of5`said' key center stud to furthrfrestrictthe type-of key' that can beV used to operate saidrleas imeans,v alift'r spring mounted at 'one-eidflon"-aA studi secured `to Avsaid guide bracket and4 cooperating at theotherf'en'd with said lifter blo'c'kgsai'd'Spring"beinglpbsitone'dl tobe engaged intermediateits endsbyl' a"y key rotated about said key center stud and effective when engagedby a key to'move said lifter block to an' operated'position, means attached to'said lifter .block for operatingY said dog to its released position in' response to movement'of said dog'ito its*operatedposition,V and other means onsaid lifter block cooperating with theV key to -restore' said lifter blockto a predetermined normal posi tionA beforefthe keypan be rotatedY to the" position in which it can b'e'withdrawn from' the 'key open.. ing.

5; In an electric lock forfswitchesincluding".thel usual electrically controlled locking'doig, thef'corn-V binationof meansI operable by the" same'V key4 which is used to operatethesvvitc'h'padlock for releasing said dogincludin'g'fa' lifter blockeffec-rr tive when operated to 'one' position'for'v moving said dog to its'releasd'position, yieldable'fmeans acting' to'transmit force'from the key t'o' the block, said means being'so constructed'that said block" 'can be VVopera'ted'to itsV one position byY keys havingivarying degrees of wear, and key registerA means on said lifter block for'limiting operation of said'block to'predetermined types of keys.v

casing opposite an opening provided in said Wall.,

a key center stud secured to said bracket, a lifterspring pivotally attached at one end to said guide'E bracket and cooperating at'the other end Withi said lifter block, said springbeing positioned 'toi' be operated by a key disposed on saidv keycenter'- stud and'eiiective when operated to operate said lifter block, means attached to'said lifter blockA and effective when said block is operated to operate saiddog to its released position, saidspring'V being' proportioned to provide thenecessaryf stroke *required to move said dog to 4its'released position when the release is operated by keys! havinga' predetermined maximum permissible l amount of Wear, and'to deflect after thedog reachesA its released position when the release means is operated by' keys having less Wear, and latch means cooperating with said lifter block-il and effective when said lifter 'block is operated to the-position -in which said dog is released to sub-21 sequently latch said lifter block in its'dog releas`' ing position until said latch is 'manuallyoperatedl to release said lifter block.

7. In an electric lock for switches' including the4 usual electrically controlled locking dog; the 'combination of' means operable v'-by 'the same' key which is used to operate the switchrpadlockfir moving said dog to a released position including a'lifter block effectivewhen operated'to one position for moving said dog'to its released position', yieldable means acting to transmit force'from' the key to the block; said means being so' constructedv that said blockcan be 'operatedtoits' one position by keys having varying degrees'of Wear, and a latch biased to a'latching position and effective when said lifterblo-ck is operated to said one position to subsequently retain said lifter block in said one position until said latch is operatedeto -release said lifter block.

8. In an electric'lock for switches includingzthe usual electrically controlled locking dogf' the combination of means' operable by the same key,`

which is used to operate the switch padlock for releasing -said dogincludinga lifter block'feffectivefwhen operated to one position for' moving said `dog to its released position, yieldable means actingV to transmit force from' the" key" to' the block, said means being so' constructed'lthat'said block can be operated toits onel position by'keys having varying degrees of wear', key register means on said lifter block for'limiting `operation of said block to predetermined types of keys; and

alatch biased to av latching position and effective when said li'fterblock'is operated tos'aid'one pfov sition -tosubsequ'ently retain said lifter block'in saidoneposition until Vsaid latch'is operatedto release said lifter block. p

9. In an electric'lock-'for switchesincluding the' usual electrically'controlled locking dog, the combination of means operable b'yj'the saine lkey which isused :to operate theswitchpadlock for relea's-l 10 Number block in the one position until said latch is operated to release said block.

WILLIAM C. MCWHIRTER.

REFERENCES CTTED The following references are of record in the le of this patent:

UNITED STATES PATENTS Name Date 1,649,512 Cutuli NOV. 15, 1927 

